Japanese Laid-Open Patent Application Publication (hereinafter referred to as Kokai) Hei 4-348143 and Kokai Hei 7-102075 disclose composite silicone rubber particles that consist of silicone rubber particles, the surfaces of which are covered with fine particles of metal oxide. Furthermore, Kokai Hei 7-196815 discloses composite silicone rubber particles that consist of silicone rubber particles, the surfaces of which are coated with fine particles of silicone resin. In comparison to conventional silicone rubber particles, the aforementioned composite silicone rubber particles exhibit better flowability, and may impart to rubbers, plastics, coating materials, inks, waxes, cosmetic materials, etc. such properties as thermal resistance, cold resistance, weather resistance, water repellency, lubricity, mold-release properties, inner-stress relaxation properties, etc.
However, to provide excellent flowability, low aggregation, and good compoundability, such composite particles have to contain fine silicone resin particles in combination with fine metal-oxide particles. In this case, however, they become unfavorable for cosmetic use. This is because the addition of the aforementioned particles imparts the tactile feeling of hardness to the cosmetics and leads to loss of the satisfactory tactile feeling of softness expected from cosmetic products. Furthermore, addition of such particles impairs an absorption of oil-and fat such as sebum.
Furthermore, Kokai Sho 64-14250 discloses composite silicone rubber particles that consist of silicone gel particles, the surfaces of which are covered with silicone rubber particles. However, the aforementioned composite particles have low flowability and dispersibility, are difficult to attach to various materials, and cannot easily acquire lubricating and sliding properties.
Therefore, it is an object of the present invention to provide composite silicone rubber particles exhibiting excellent flowability and dispersibility, and in case of adding the particles to various materials, improving tactile feeling, reducing inner stress, and providing lubricating and oil-and-fat absorption properties. Another object is to provide an efficient method of manufacturing the composite silicone rubber particles with the aforementioned properties.